Scientists skeptical about rush to build sand barriers

Gregory Stone, director of the Coastal Studies Institute at Louisiana State University, warned that scooping sediment out of the sea bottom could accelerate wave action.

"It's not advisable to go out into shallow water and dredge and not expect potential negative impacts," Stone said. "That's going to increase the energy of the waves."

Such worries prompted the Interior Department to conclude: "We do not think the risks inherent in proceeding without more environmental study and knowledge are acceptable."

Coastal scientists and oceanographers were brought in this week to present their views on the berm proposal to state and federal responders. Many said they were frustrated, wondering why their expertise was not brought to bear sooner.

"You cannot do this without some sort of reasonable quantification as to what will happen," Stone said. " I understand we are in a jam right now, but, good Lord, we have sophisticated computer models that can do this in a matter of weeks.… It's sort of unconscionable that we've gone well over a month without scientific input."

Denise Reed, interim director of the Pontchartrain Institute for Environmental Science at the University of New Orleans, said that given the construction timelines, expectations that the berms will stop oil are unrealistic.

"There is a public sense that this is the solution that we need," she said. "I found this proposal extremely difficult to evaluate because it's so idealized and conceptual.… We are not going into it with our eyes wide open."